The prevention and treatment of decubitus ulcers is an important aspect of health care. Patients who are comatose, diabetic, paraplegic or otherwise suffering from serious impairment of the neural and vascular systems are at risk of developing these pressure sores. Once the ulcer has progressed beyond the initial indications, treatment is difficult, long, and costly.
Studies have indicated correlations between thermal characteristics of skin and potential decubiti formation. These appear to be related to both increased temperatures and decreased blood flows to potential ulcer forming areas in compromised patients.
When an area of skin is compressed for a period of time the normal blood flow to the region is reduced. The amount of reduction depends on the applied pressure. The reaction of the tissues is a function of the pressure intensity, time of application and frequency of application. Under normal conditions, these factors produce a reaction of involuntary motion which tends to relieve the pressure from the affected region and redistribute it to another skin location. These motions occur with sufficient frequency so that no permanent tissue damage results. When the pressure is relieved, a hyperemic response occurs as the body seeks to compensate for the oxygen deprivation and metabolite accumulation by an increased blood flow. This response normally subsides in a few minutes as the tissues are restored to normal function. A component of this increased blood flow is a change in skin temperature during the response. Studies have shown that there is a pressure and time relationship for these events, and that the greater the applied pressure, the shorter the time interval of application must be if the effects are to be reversible.